EE-364 Lab #2 State Machine Multiplier - Capitol College Faculty ...

We start with loading zeroes into the subtotal. To do this loading we enable b and c. Wethen add A = a 3 a 2 a 1 a 0 to the subtotal if b 3 is one. We then multiply the subtotal by two(2) by enabling d and e. We then add A = a 3 a 2 a 1 a 0 to the subtotal if b 2 is one. Thissteps in this form of the algorithm are the opposite to those of the above steps:0 0 0 0 0 0 0 0 (clear subtotal)0 0 0 0 1 0 0 1 ( b 3 =1, add A to subtotal )0 0 0 1 0 0 1 0 ( multiply subtotal by 2 )0 0 0 1 0 0 1 0 ( b 2 =0, don’t add A to subtotal )0 0 1 0 0 1 0 0 ( multiply subtotal by 2 )0 0 1 0 1 1 0 1 ( b 1 =1, add A to subtotal )0 1 0 1 1 0 1 0 ( multiply subtotal by 2 )0 1 1 0 0 0 1 1 ( b 0 =1, add A to subtotal )The (detailed) circuit for the multiplication is shown in Figure 2. The task for the student is toprogram the Control ROM (PROM32) (right-click on PROM32, select EditPROM/RAM, see Figure 3). The input to the Control ROM is a counter along with theoutput from a shifter whose input is b 3 b 2 b 1 b 0 . The output of the control ROM is a numberof control signals that control the inputs to the summer, the operation of the shift register andthe Control ROM counter. The detailed specification of these signals is in Table 1.Signal Data Line Descriptiona D0 Enable A onto left busb D1 Enable 0 onto left busc D2 Enable 0 onto right busd D3 Enable subtotal onto left buse D4 Enable displayf D5 Enable shift register for shifting or loading (active low)g D6 Shift (high)/Load (low)h D7 Enable State IncrementTable 1. Control outputs of Control ROM.4